1. Field of the Invention
This invention relates to a device for displaying exposure information within the viewfinder of an automatic exposure control camera, and more particularly to an exposure information display device within the viewfinder of a camera capable of changing over the exposure controls by a shutter speed priority automatic exposure control mode, an aperture priority automatic exposure control mode and a program automatic exposure control mode.
2. Description of the Prior Art
In the prior art, the automatic exposure control modes of a camera includes a shutter speed priority automatic exposure control mode in which aperture value is automatically controlled so that a proper exposure may be provided in accordance with a preset shutter speed and the brightness of an object, an aperture priority automatic exposure control mode in which shutter speed is automatically controlled so that a proper exposure may be provided in accordance with a preset aperture value and the brightness of an object, and a program exposure control mode in which aperture value and shutter speed are automatically controlled by a combination of an aperture value and a shutter speed predetermined with respect to a metered exposure value (EV). Cameras are known which are capable of selectively accomplishing photography by more than two of these modes and in such cameras, it is desired that exposure information in conformity to the mode used during photography be displayed within the viewfinder.
U.S. Pat. No. 4,118,723 discloses an exposure data display device within the viewfinder of a camera in which the photography by a shutter speed priority automatic exposure control mode and the photography by an aperture priority automatic exposure control mode can be selectively changed over. In this device, two display portions for displaying a preset aperture value and a preset shutter speed, respectively, and a third display portion for displaying a controlled aperture value or shutter speed are provided within the viewfinder and a shutter element is shown for shielding the display portion for displaying the preset shutter speed when a mode selector selects the aperture priority automatic exposure control mode. This technique is applicable to the display in a camera having the photographing functions by two types of modes, but with respect to a camera having the photographing functions by three types of modes, i.e. the aperture priority, the shutter speed priority and the program automatic exposure control mode or a camera having the photographing functions by four types of modes, i.e. said three modes and a manual mode in which aperture value and shutter speed are manually set, this technique would bring confusions to the photographer due to inundation of information unless it is further improved.